Discrete electronic components in the form of surface mounted devices and passive chip components are widely used in the electronics industry. Such components may be formed of ceramic, for example. In many applications, the components carry a large power load in relation to the components' size. The high power density requirements may result in premature failure of the components due to heat stress and thermal expansion. For example, repeated thermal expansion may cause cracking in the solder joints at the terminals of the components, as well as oxidation and intergranular corrosion.
A typical power rating of a ceramic resistor chip, such as a model 2512 chip, is less than or equal to one watt per chip from room temperature up to 70° C. However, above 70° C. the power rating steadily falls to 0 watt at about 155° C. Temperature cycling testing reveals that such chips cannot pass a test including 1000 cycles between −40° C. aid 150° C. Many automotive applications require a high power chip to operate at an application temperature range of 85° C. to 105° C., which the chips are not able to reliably withstand.
One known solution to the chip overheating problem is to use multiple chip components connected together in series or parallel. However, this adds to the component cost and negates the advantage of surface mounted devices, which is in occupying as little space as possible.
What is needed in the art is a method of decreasing the heat stress on discrete electronic components used in high power applications.